Mitral valve stenosis

What’s that?

Mitral valve stenosis is a heart defect in which the opening between the left atrium and the ventricle is narrowed. It causes a decrease in the velocity of arterial blood flow. Pathology occurs due to a reduction of the fibrous ring, complete fusion, or an increase in the size of the mitral valve (MV) and a decrease in the mobility of its leaflets. Acquired form of pathology occurs, on average, in 50-80 people per 1000, mainly women over 50 years of age suffer.

About the disease

When the MV opens, blood flows from the atrium into the ventricle, and after it closes, it is pushed out into the aorta. In mitral valve stenosis, the opening between these heart chambers loses its ability to open fully, which becomes an obstacle to natural blood flow. As a result, blood volume and pressure in the left atrium and its cavity increase. With severe pathology, the pressure in the lungs’ blood vessels increases. It provokes the development of heart failure, accompanied by an accumulation of fluid in the respiratory organs and a decrease in oxygen supply in the blood.

Types of mitral valve stenosis

Depending on the shape of the narrowing of the orifice, two types of mitral stenosis are distinguished:

“Jacket loop” – the valve leaflets are thickened and partially fused. During surgical intervention, their separation is not difficult.
“Fish mouth” – overgrown connective tissue gives the opening the shape of a narrow funnel. This defect is poorlyamenable to surgical correction.

Mitral valve stenosis goes through several successive stages in its development.

Compensatory, the orifice area exceeds 3 square centimeters—moderate degree of narrowing of the orifice with asymptomatic course. Due to hypertrophy of heart muscle, the heart defect is compensated.
Sub-compensatory, the orifice area is 2.3-2.9 square centimeters. The narrowing of the orifice progresses, compensation mechanisms are exhausted, and the patient shows the first signs of pathology.
Moderate, the orifice area is 1.7-2.2 square centimeters. Signs of pathology appear even at rest.
Decompensation, the orifice area is 1.0-1.6 square centimeters. Severe, rapidly worsening pulmonary hypertension and right ventricular failure.
Terminal, the lumen is virtually closed. Irreversible changes appear, leading to lethal outcomes.

Depending on the mechanism of development, three forms of mitral stenosis are distinguished:

Commissural-fibrotic changes appear along the edge of the mitral valve leaflets, leading to their gradual fusion and stenosis formation.
Valvular – the mitral valve orifice acquires a slit-like shape. The pathology is characterized by a severe clinical course, even in cases where the mitral valve retains its normal area.
Chordal-valve damage occurs at the level of the leaflets (fibrosis begins) and chords (tendon chords shorten, thicken, and fuse. Gradually, a funnel-shaped rigid valve is formed, and mitral insufficiency also occurs.

Mitral stenosis can also be:

isolated;
combined with MV insufficiency or damage to other heart valves (mitral-tricuspid or mitral-aortic heart defect).

Depending on the timing and cause of the malformation, the malformation can be congenital or acquired.

Symptoms of mitral stenosis

At the initial stages of the pathological process, there are no signs of stenosis. With the progression of narrowing, there is an increase in pulmonary pressure and signs of “mitral” pallor: the tips of the auricles, nose, and fingers acquire a bluish tint and become cyanotic. Physical exertion leads to increased cyanosis. The human skin takes on a grayish tint due to extremely low minute blood volume (the amount of blood ejected into the aorta per minute).

The clinical signs of mitral stenosis in these stages are noted:

tachycardia;
increased fatigue;
constant chest pains;
cough with blood in the sputum;
shortness of breath on physical exertion and then at rest;
loss of voice due to compression of the recurrent nerve;
heart rhythm disturbances such as atrial fibrillation and extrasystole.

Signs of pathology increase as it develops. In case of severe stenosis, orthopnea appears. These are nocturnal attacks of pronounced shortness of breath in a horizontal position so that a person can sleep only sitting or with his head elevated.

Causes of mitral stenosis

Atrioventricular stenosis develops in 80% of cases after the patient has suffered from rheumatism. Rheumatic myocardial damage usually manifests at a young age, and the development of clinically significant mitral stenosis occurs after 10-30 years. Less common causes leading to MI include:

infectious inflammation of the inner lining of the myocardium (endocarditis);
congenital heart defects (Lutembacher syndrome);
calcinosis of the mitral valve leaflets and annulus;
aortic insufficiency;
left atrial myxoma;
clots in the blood vessels of the heart;
myocardial trauma;
atherosclerosis;
syphilis.

Diagnosis

To diagnose mitral stenosis, the patient must undergo a complete examination.

Initial appointment with a cardiologist and medical history taking. The doctor talks to the patient, clarifies the presence of complaints, and auscultates the heart.
ECG. Electrocardiographic study can detect heart rhythm disorders, left atrial hypertrophy, etc.
Echocardiogram. With the help of an echocardiogram, the specialist can detect the thickening of the walls and fibrous ring of the mitral valve, blood clots in the left atrium, and the degree of enlargement of its chamber.
Chest X-ray. This study is performed to determine the shape and size of the heart, identify areas of calcium deposition on the mitral valve, and study the state of the lungs.

Laboratory tests are auxiliary and aim to clarify the state of organs and tissues and identify the background and associated pathologies. If necessary, related specialists are involved in the diagnosis.

Treatment of mitral stenosis

Therapeutic measures for this form of heart defect are divided into conservative and surgical. They are used in parallel, as medication support of the patient is essential in preparation for and after surgery.

Conservative treatment

Conservative therapy includes drugs aimed at stabilizing the cardiovascular system:

blood pressure medications;
diuretics to prevent fluid retention in the blood vessels;
cardiac glycosides that increase the contractile function of the left ventricle;
drugs with anticoagulant and antiplatelet action, preventing increased thrombosis.

The choice of medications is made by a specialist based on the diagnosis results.

Surgical treatment

These operations are considered for the mitral stenosis treatment:

Closed mitral commissurotomy, dilation of the MV with a special surgical dilator;
Reconstructive valve-preserving surgeries to restore the function of the valve damaged by stenosis using suture plastic techniques.
transcatheter balloon valvuloplasty.
valve replacement with a biological or mechanical prosthesis – is the most effective surgical intervention. During the surgery, the valve is accessed through the atrial septum, lateral wall, or roof of the left atrium.

All these surgical options are available in more than 550 hospitals worldwide (https://doctor.global/results/diseases/mitral-valve-stenosis). For example, mitral valve replacement is performed in 29 clinics across Turkey for an approximate price of $19.0 K (https://doctor.global/results/asia/turkey/all-cities/all-specializations/procedures/mitral-valve-replacement-mvr).

Prevention

Measures to prevent the development of MS include:

leading a healthy lifestyle: sports, proper nutrition;
avoiding bad habits;
timely visit to a specialist in case of colds.

Rehabilitation

On the first day after surgery, the patient is in the intensive care unit and then transferred to the cardiology department under the supervision of the attending physician. During this time, the operated person must strictly follow all medical recommendations. Before discharge, he will draw up an individual rehabilitation program at home. In addition, they should be observed by a cardiologist on an outpatient basis, have an echo once a year, follow the standard principles of prevention, and lead a healthy lifestyle.